As the turbine housing used for the turbocharger, the one made of a casting is common. In contrast, a turbine housing made of a sheet metal is disclosed in Patent Literature 1, for example. This is illustrated in FIG. 10 to FIG. 12.
As illustrated in FIG. 10 to FIG. 12, a turbine housing 1 includes a scroll portion 2, a turbine outlet piping 7, a bypass passage piping 6, and a turbine outlet flange 4. The scroll portion 2 constitutes a spiral exhaust gas passage, and the turbine outlet piping 7 is projected from this scroll portion 2 and constitutes a turbine outlet 2b serving as the outlet for exhaust gas. The bypass passage piping 6 is projected from the scroll portion 2 in order to constitute a bypass passage 5 bypassing the scroll portion 2 and an external exhaust gas passage (not illustrated), and is separately juxtaposed with the turbine outlet piping 7. The turbine outlet flange 4 is supported by the turbine outlet piping 7 and bypass passage piping 6. Note that, in the view, reference sign 2a indicates a turbine inlet, and reference sign 3 indicates a turbine inlet flange.
Then, the turbine housing 1 supports the turbine outlet flange 4, which is made of a casting and relatively heavy, with two pipings, i.e., the turbine outlet piping 7 and the bypass passage piping 6.